Effect of nitrogenation on the magnetostriction of Y2Fe17, Pr2Fe17 and Nd2Fe17

Magnetostriction measurements on nitrogenated Y2Fe17, Pr2Fe17, and Nd2Fe17 from cryogenic temperatures to 300 K yield surprising results. Even though Curie temperatures, magnetizations and magnetic anisotropies of the R2Fe17 compounds (R=Y,Pr,Nd) are all substantially increased by nitrogenation, the magnetostrictions are frequently unchanged or reduced. In Pr2Fe17, a large reduction in the magnetostriction is observed. In Nd2Fe17, Y2Fe17, and all nitrogenated samples, the magnetostriction is positive at high temperatures and decreases with decreasing temperature at low temperatures, revealing a strong negative basal plane λγ,2 constant in a background of a positive average magnetostriction. (orig.)